1. Field of the Invention
The present invention relates to and is based on a method for transmitting over a bidirectional radio channel.
2. Description of the Background Art
It is known that for transmission of digital data such as digitized speech or other digital information over a (bidirectional) shortwave radio channel in both transmission directions, the digital data to be transmitted, which is transmitted over the radio channel alternately in forward and reverse directions (simplex operation), can be processed according to a predetermined data transmission protocol, also referred to below as DÜP, and divided into individual data packets (e.g., according to A. S. Tanenbaum, Computer Networks, Prentice Hall, Englewood Cliffs, 1981, pages 136 ff.; European Patent No. 730,356). This digital data for transmission can also be processed first according to another data transmission protocol at a higher level, i.e., a higher-level data transmission protocol, also referred to below as DÜPHE, e.g., according to the known TCP/IP method (transmission control protocol/Internet protocol). For optimizing data transmission over such a bidirectional radio channel, there have already been proposals to determine the bit error rate at the receiving end and transmit it back to the transmitter, where the length of the data packets is revised accordingly (older German Patent Application 196 51 593.9). Furthermore, it is also known that in a data transmission system that operates by the duplex method and has two separate transmission channels, the data rate can vary as a function of the prevailing data occurrence to make the transmission less sensitive to interference (U.S. Pat. No. 5,513,213).
Depending on the type of digital data to be transmitted and the higher-level data transmission protocol (DÜPHE) processing the data, such as TCP/IP, the resulting data packets and acknowledgments in both transmission directions may vary greatly in length and frequency, and thus data throughput can be greatly impaired even when using the above-mentioned optimization of data transmission with the data transmission protocol DÜP.